Ireland's Cian O'Connor and Blue Loyd picked up eight faults, but with no penalties to carry from the first round, the Meath rider qualified as one of the top 45 for Monday afternoon's semi-final of the jumping event at Greenwich Park.
Cork's Billy Twomey, who was fourth to jump on the challenging Nations' Cup track, also collected eight penalties aboard Tinka's Serenade, but with four faults added from Saturday's first qualifier, he failed to make the cut for the third qualifying round.
However, Twomey moves on to the ten-strong reserve list, should any of the qualified combinations drop out before Monday’s competition.
Monday will see the top 45 riders battle it out for a place in Wednesday's individual final, with only the best 35 qualifying.
All qualified riders start on a zero score in the first round on Wednesday, with the top 20 then moving on to the last jumping round, where medals will be decided.
British riders Nick Skelton and Ben Maher were in a tie for first place with Saudi Prince Abdullah Al Saud and several others after 15 went clear.
Saudi Arabia also lead the way in the team event with just a single-point penalty from host nation Great Britain, Netherlands, Sweden and Switzerland, who each had four penalties.